Introduction
Syncope and collapse history is a high-yield OSCE station that requires you to distinguish between benign vasovagal episodes and life-threatening cardiac or neurological causes. Examiners expect you to take a structured eyewitness account, ask about red flags, and address driving restrictions.
💎 Clinical Pearl
Always ask for a witness account — what did they see? Many patients lose consciousness and cannot self-report their collapse accurately. "Was anyone with you when it happened? What did they see?"
Three-Part Approach: Before, During, After
Before the Collapse (Prodrome)
| Feature | Suggests |
|---|---|
| Gradual onset: nausea, sweating, tunnel vision, light-headedness | Vasovagal (neurocardiogenic) syncope |
| No warning — abrupt collapse | Cardiac arrhythmia |
| Aura, strange smell, deja vu, rising abdominal sensation | Epileptic seizure (partial onset) |
| Standing up or position change | Orthostatic hypotension |
| Trigger: heat, crowded room, prolonged standing, fear, pain, venepuncture | Vasovagal syncope |
| Exertion at time of collapse | Cardiac cause until proven otherwise |
During the Episode
| Feature | Suggests |
|---|---|
| Duration less than 30 seconds | Syncope (cardiac or vasovagal) |
| Duration over 5 minutes | More likely seizure |
| Jerking movements: brief myoclonic jerks (seconds) | Convulsive syncope (can occur in vasovagal) |
| Sustained tonic-clonic movements | Epileptic seizure |
| Tongue biting (lateral) | Epileptic seizure |
| Incontinence | Can occur in both syncope and seizure |
| Cyanosis | Prolonged seizure or cardiac cause |
After the Episode (Postictal Phase)
| Feature | Suggests |
|---|---|
| Rapid recovery (seconds to minutes) | Syncope (vasovagal or cardiac) |
| Prolonged confusion, drowsiness (minutes to hours) | Epileptic seizure (postictal phase) |
| Focal neurological deficit | Todd's paresis (post-seizure) or stroke |
| Headache | Seizure |
| Muscle aches | Tonic-clonic seizure |
Causes of Syncope — Main Differentials
🧠 Mnemonic
VANCE — Vasovagal, Arrhythmia, Neurological, Cardiovascular structural, Everything else (orthostatic, metabolic)
- Vasovagal: most common cause; triggered by emotion, pain, prolonged standing
- Arrhythmia: AF, VT, SVT, complete heart block, long QT — important to exclude
- Neurological: seizure, TIA/stroke, subarachnoid haemorrhage
- Cardiovascular structural: aortic stenosis, HCM, massive PE, cardiac tamponade
- Everything else: orthostatic hypotension, hypoglycaemia, vasodepressor drugs
Cardiac Red Flags
⚠️ Red Flag
Any of these features = cardiac cause until proven otherwise. Urgent cardiology review and prolonged cardiac monitoring are required:
- Collapse during exertion
- No warning prodrome (abrupt onset and recovery)
- Collapse preceded by palpitations or chest pain
- Family history of sudden cardiac death under 40
- Known structural heart disease (HCM, aortic stenosis)
- Abnormal ECG (long QT, delta wave, LBBB, complete heart block)
- Age over 60 with new syncope
Systematic Additional History
Cardiovascular Screen
- Palpitations before or after the episode
- Chest pain or dyspnoea
- Known cardiac disease, pacemaker, ICD
Neurological Screen
- Aura, tongue biting (lateral = seizure), postictal confusion
- Previous seizures, head injury
- Focal weakness after the episode (Todd's paresis)
Drug and Metabolic Screen
- Antihypertensives, diuretics (orthostatic hypotension)
- Insulin or oral hypoglycaemics (hypoglycaemia)
- QT-prolonging drugs: amiodarone, sotalol, haloperidol, macrolides
- Alcohol (lowers seizure threshold)
- Recreational drugs
Situational Syncope
- Micturition syncope (vagal), cough syncope, carotid sinus hypersensitivity (collar turning)
Recurrent Episodes
- Frequency, any pattern or trigger
- Previous investigation results
DVLA Driving Restrictions
⚠️ Red Flag
You must advise on driving if relevant — failing to do so loses marks.
- First unexplained syncope, no cardiac cause found: Group 1 (car) — do not drive for 4 weeks. Group 2 (HGV/bus) — off for 3 months with investigation.
- Cardiac arrhythmia causing syncope: do not drive until cause identified and treated — then case-by-case.
- Epileptic seizure: do not drive for 1 year seizure-free (Group 1); 5 years seizure-free off medication (Group 2). Patient must inform DVLA.
- Vasovagal syncope with clear trigger: no DVLA notification required if clear prodrome and avoidable trigger.
How to Present
"This is a 23-year-old woman with a first episode of collapse while standing in a crowded shop. She had a 30-second prodrome of nausea, sweating, and tunnel vision before losing consciousness for approximately one minute, with rapid full recovery. No tongue biting, no postictal confusion, no palpitations, and no chest pain. No family history of sudden cardiac death. No exertional component. This presentation is consistent with vasovagal syncope. I would arrange a 12-lead ECG and advise her not to drive for 4 weeks pending further assessment."
"What features distinguish a vasovagal syncope from a cardiac arrhythmia?"
Vasovagal syncope typically has a gradual onset with a clear prodrome (nausea, sweating, tunnel vision), a clear trigger (prolonged standing, pain, heat), rapid full recovery within seconds to minutes, and occurs predominantly in young people in upright postures. Cardiac arrhythmia presents with abrupt loss of consciousness without warning, may be preceded by palpitations or chest pain, can occur in any position including supine, and is more common in older patients or those with known cardiac disease.
"How do you differentiate a seizure from a convulsive syncope?"
Convulsive syncope can occur in vasovagal episodes as brief myoclonic jerks lasting a few seconds due to cerebral hypoperfusion. A true epileptic seizure features: sustained tonic-clonic movements lasting over 1 minute, lateral tongue biting, prolonged postictal confusion lasting 10-30 minutes or more, muscle aches, and possibly an aura preceding the event. Brief myoclonic jerks, no postictal state, and rapid recovery suggest convulsive syncope rather than epilepsy.
"What DVLA advice would you give a patient after a first unexplained syncope?"
For a Group 1 licence (car drivers), a patient with a first unexplained syncope should not drive for 4 weeks. If a cardiac arrhythmia is identified as the cause, driving is not permitted until the cause is treated and the patient has been assessed. If the diagnosis is vasovagal syncope with a clear identifiable trigger and prodrome, no DVLA notification is required though the patient should avoid the trigger while driving.
"What ECG findings would make you concerned about a cardiac cause for syncope?"
Concerning ECG findings include: prolonged QTc (over 440 ms in men, 460 ms in women) suggesting long QT syndrome, delta wave (pre-excitation, Wolff-Parkinson-White), right bundle branch block with ST elevation in V1-V3 (Brugada syndrome), complete heart block, left bundle branch block (new), or evidence of left ventricular hypertrophy suggesting hypertrophic cardiomyopathy.
Related guides: Chest Pain History OSCE | ECG Interpretation OSCE | DVLA Fitness to Drive OSCE | Neurological History OSCE